Coupling for power take off shaft



Dec. 25, 1962 B. M. SILVERBERG ETAI. 3,070,393

COUPLING FOR POWER TAKE OFF SHAFT Original Filed Aug. 8, 1956 INVENTORS BERNARD M.S|LVERBERG 8| FRANK D. JONES 330 393 Patented Dec. 25, 1962 3,076,393 CGUPLING FfiR PfiWlER TAKE ()FF SHAFT Bernard M. Silverberg, Milwaukee, Wis., and Frank D. Jones, Moiine, iii, assiguors to Deere & Company, Moiine, llilL, a corporation of illinois Original application Aug. 8, 1956, Ser. No. 602,881, new Patent No. 2,959,938, dated Aug. 30, 1960. Divided and this application Dec. 8, 1959, Ser. No. 858,147 3 Claims. (Cl. 287-130) This invention relates to a coupling mechanism and more particularly to a coupling mechanism for use with a power take-off shaft of a tractor and a drive shaft of a trail-behind implement.

This is a division of pending application Ser. No. 602,881, filed August 8, 1956, now Patent No. 2,950,938.

In recent years there has been a great deal of work done in providing simple connections between tractors and the associated trail-behind implements, the over-all purpose being to provide connections which may be easily attached or detached from the implement or the tractor. With the advent of the power lift system on the tractor the more recent trend is to provide connections between the tractor and implement which may be operated without the operator leaving his station on the tractor and in many instances by use only of the power of the tractor. Most of this latter trend however, pertains to the connections between the drawbar or draft link members of the tractor and the associated tongue or draft connections on the implement. In a considerable number of the implements a driving mechanism is provided in the implement to operate various parts on the implement itself. The drive source for the drive mechanism normally comes from the power take-off shaft also provided on the tractor. It would logically follow that it would be desirable to provide a quick attach and detach coupling between the power take-off and the drive shaft on the implement to operate in conjunction with the simple draft connections between the tractor and implement.

It is therefore the primary object of this invention to provide a coupling on the power take-off shaft which may be easily and simply detached from the power take-off shaft.

It is also an object of this invention to provide in the above type of coupling means for detaching it from the power take-off shaft which requires no tools and very little effort on the part of the operator.

It is still a further object of the invention to incorporate in the above type of coupling biasing means which will normally operate to lock the coupling on the shafts but which may by a small effort be sufiicient to overcome the biasing force to unlock the coupling from the shaft.

Other objects and advantages of the invention will become apparent to those skilled in the art as the nature of the invention is more completely understood from the following detailed description and accompanying drawings.

FIG. 1 is a perspective view of a rear portion of a tractor and a forward portion of a trail-behind implement and showing the coupling of the present invention. For purposes of illustration portions of the safety shielding overlying the power take-01f shaft and implement drive shaft have been removed.

FIG. 2 is an enlarged vertical sectional view of the coupling and power take-off shaft.

FIG. 3 is a sectional view taken along the line 33 of FIG. 2.

A tractor is of a conventional type having transversely spaced apart rear wheels 11 and 12 interconnected by suitable axle structures, as at 13. Provided on the tractor is a difierential or gear transmission, in-

dicated in its entirety by its housing 14, wihch operates to drive a power take-off shaft 15. Beneath the power take-off shaft is a tractor drawbar 18 which extends rearwardly from the tractor frame and is connected at its rear terminal end by means of a drop pin 19 to the forward end of an implement tongue '28. A clevis type connection 21 is provided at the forward end of the tongue 28 to receive the drop pin 19. Positioning guides or a stationary drawbar 22 is also provided on the tractor. Other features of the tractor such as the hydraulic unit, indicated in its entirety by the reference numeral 23, and the seat structure 24 are of conventional design.

The trail-behind implement, while not shown, is of the type requiring a drawbar type of connection for pulling the implement in trail-behind fashion and of a type having operating mechanism which receives its power source from the power take-off shaft 15 of the tractor. There are several types of implements which fall in this category such as for example corn pickers, hay balers, manure spreaders and others. Consequently, since the type of implement is unimportant for purposes of this invention, only the extreme forward end of the implement as represented by the tongue 20 and a power shaft mounted under a housing 30 is shown. The housing 30 is supported on suitable brackets 31 fixed to the tongue 20 and obviously serves as safety shielding as well as housing for the power shaft. The power shaft is connected to the power take-off shaft 15 by means of a drive shaft 32 which has its rear end connected to the power shaft by means of a conventional type universal joint, not shown but positioned under a conventional safety shielding 33 just forward of the housing 30. The for ward end of the drive shaft 32 is connected to the power take-off shaft 15 by means of the snap-on type coupling 48 which is the subject matter of the present invention.

It should here be noted that the implement is shown as being connected to the tractor by a clevis type con nection at 19 and 21. This simplified type of connection is shown for purposes of illustration only and it should be recognized that other types of draft connections would operate efficiently with this type of coupling. As a matter of fact, it is possible that this type of coupling would receive its greatest acceptance in conjunction with those types of implements which are adapted to be mounted on the tractor or by means commonly known in the trade as the standard three point type of hitch.

The coupling 40 is composed of a radially extending member 41 mounted on the power take-off shaft 15. The member 41 has a hub 42 apertured as at 43 to receive a pin 44 which extends through the aperture 43 and a corresponding registrable aperture 45 in the power takeoff shaft. The radial member 41 has a radially extending plate or flange portion with its outer peripheral edge having a toothed section as at 46. Also included in the coupling mechanism is a corresponding or second radial member indicated in its entirety by the reference numeral 58 which is fixed to the drive shaft 32 by means of a universal type joint 51, part of which includes bifurcated leg portions 52, 5'3 integral with the radial member 50. The member 58 is further characterized by having a radially extending plate or annular portion 54 having a forward surface 55 lying normally adjacent to the rear plate surface 47 of the radial member 41, and an axially extending flange 56 extending forwardly and overlying the outer periphery of the radial member 41. The flange 56 has an internal toothed surface 57 which receives the teeth of the radial member 41. When in mesh the toothed surfaces 46 and 57 will cause the radial members 41 and 50 to rotate in unison. Also, this permits, unless otherwise restricted, the radial member 41 to move axially relative to the radial member 50.

A plurality of angularly spaced apertures 60 are proa vided in the flange 56 to receive ball or locking elements 61 and to permit the balls to move radially. The balls 61 are characterized by having a substantially larger diameter than the thickness of the flange 56 so that a portion of the ball will extend radially inwardly or outwardly of the flange.

Associated with the member 50 is an annular ring 65 which is axially slidably mounted on the member 50. The ring 65 has an internal surface 66 which normally rides adjacent to the peripheral edge of the annular portion 54 and an internal surface 67 which normally rides adjacent to the outer periphery of the flange portion 56, the ring being suitably stepped radially inwardly as at 68 to provide a radial surface between the cylindrical surfaces 66, 67. The forward end of the annular ring 65 is provided with an internal cam surface 69 which engages the locking or ball elements 61. The annular ring 65 is restricted in its axial movement in the first instance by the radial surface 68 which acts as a stop in one direction and in the second instance by a snap ring 72 which is seated in a suitable slot 71 in the ring 65, the ring 72 acting as a stop in the opposite direction. A plurality of angularly spaced indentations 75 is provided in the forward portion of the annular member 54 for receiving compression springs 76, one end of which is seated in the indentation 75 and the other end of which projects from the face of the annular member to engage the radial surface 68 of the annular member 65.

The coupling operates in the following manner. To engage the coupling to cause the power take-off shaft and the drive shaft 32 to rotate in unison, the annular ring 65 is first drawn manually rearwardly to compress the springs 76. This permits the balls 61 to move outwardly against the cam surface 69 to remove them as obstructions against sliding the member over the outer toothed surface 46 of the member 41. Upon the radial surface engaging the surface 47 of the plate 41, the ring 65 may be released to cause the cam surface 69 to drive the balls or locking elements 61 radially inwardly and forwardly of the radial member 41, thereby locking the coupling elements against disengagement. To uncouple the drive shaft from the power take-off shaft the annular ring is drawn rearwardly to compress the springs thereby permitting the balls or locking elements to move radially outwardly and to clear the external edge of the teeth 46 so as to permit the member 50 to slide off of the member 41. It would be noted that the teeth 46 have a bevel which operates as a cam to move the locking members 61 outwardly. It should also be noted that under no circumstances will thering 65 be moved to a position rearwardly which will permit the locking elements 61 to be released externally from the apertures 60, nor can the locking elements 61 escape from the apertures internally, the balls being limited in their radial inward movement by the shape of the apertures 69 which causes them to seat at maximum inward position. Therefore, while the coupling may be coupled or uncoupled relatively easily, the only manner in which the parts of the coupling may be disassembled is by first removing the snap ring 72 to permit the annular ring 65 to be slid forwardly and off to the member 50.

While only one form of the invention has been shown it should be recognized that other forms and variations could exist without departing basically from the broad general principles herein disclosed. It should therefore be understood that while the preferred embodiments of the invention have been described with the view of clearly and concisely illustrating the principles, it is desired not to so limit or narrow the invention beyond that which is claimed.

What is claimed is:

1. A coupling mechanism for connecting the power take-off shaft on a tractor to an implement drive shaft comprising: a radially extending circular plate fixed to the power take-off shaft and having axial teeth on its periphery; an associated circular member fixed to the drive shaft including a radial plate portion substantially adjacent and parallel to the plate on the power takeoff shaft and an annular flange portion overlying the outer periphery of the plate with internal axial teeth engaging the teeth of the plate; locking elements carried by the flange portion movable radially to seat behind the plate to prevent axial separation of the plate and circular member; and locking element engaging means supported on the circular member and movable to a first position to cause the locking elements to seat behind the plate, and movable to a second position to permit the locking elements to move radially from behind the plate, said ele ment engaging means being biased against movement from the first to the second position.

2. A coupling mechanism for connecting the power takeoff shaft on a tractor to an implement drive shaft comprising: a radially extending circular plate fixed to the power takeoff shaft and having axial teeth on its periphery; an associated circular member fixed to the drive shaft including a radial plate portion substantially adjacent and parallel to the plate on the power take-01f shaft and an annular flange portion overlying the outer periphery of the plate with internal axial teeth engaging the teeth of the plate; locking elements carried by the flange portion movable radially to seat behind the plate to prevent axial separation of the plate and circular member; a ring member outwardly of said flange portion and movable axially to a first position to move the locking elements radially to seat behind the plate, and movable to a second position to permit the locking elements to move radially from behind the plate; and biasing means between the ring member and the circular member resisting movement from the first to the second position.

3. A coupling mechanism for connecting a drive shaft to a driven shaft comprising: a first member having a rigid plate portion with opposite radially extending surfaces, a hub portion fixed to one of the shafts, and an outer surface with axial guide means thereon; a second member abutting one of the radially extending surfaces of the first member having a hub portion fixed to the other of the shafts and an axially extending flange portion adapted to overlie the first member and to engage the axial guide means to permit relative axial movement between the two members and to effect rotation in unison of the two members said flange portion extending axially beyond the other radially extending surface of the plate portion; locking elements carried by the flange portion for radial movement relative to the first member; and locking element engaging means supported on the flange portion for axial movement between a first position to move the locking elements to sit behind said first member thereby preventing axial separation of said radial members, and a second position to permit the locking elements to disengage the first member, said locking element engaging means being biased against movement from the first to the second position and biased to said first position to automatically lock said members together upon said flange portion overlying the first member.

References Cited in the file of this patent UNITED STATES PATENTS 2,498,399 Dodge Feb. 21, 1950 2,521,701 Earle et al. Sept. 2, 1950 2,690,918 Holte Oct. 5, 1954 2,846,859 Schroter et a1 Aug. 12, 1958 2,909,047 Walterscheid-Muller et al. Oct. 20, 1959 

